$sql = 'SELECT blahblah, bla FROM databasename WHERE lat >= ? AND lat <= ? AND lon >= ? AND lon <= ?';
$params = array( $minlat, $maxlat, $minlon, $maxlon );
if ( isset( $_GET['sear'] ) ) {
    $sql .= "AND (searcher LIKE ?)";

    $params[] = '%'.$_GET['sear'].'%';

}

$sql = 'SELECT blahblah, bla FROM databasename WHERE lat >= ? AND lat <= ? AND lon >= ? AND lon <= ? ORDER BY autoinc DESC LIMIT 30';
$params = array( $minlat, $maxlat, $minlon, $maxlon );
if ( isset( $_GET['sear'] ) ) {
    $sql .= "AND searcher LIKE ? ";

    $params[] = '%'.$_GET['sear'].'%';


}